Conventionally, there is known an apparatus for producing a three-dimensional laminated object, wherein a powder layer of an inorganic or organic powdery material is formed on a base, a light beam is irradiated on a specified portion of the powder layer to sinter and cure the powdery material in the specified portion to thereby form a solidified layer and the preceding steps are repeated while moving the base up and down so that the solidified layers are laminated into a single body (see, e.g., Japanese Patent Laid-open Publication No. 2002-115004).
FIGS. 9A and 9B partially illustrate the configuration of a conventional apparatus for producing a laminated object. The laminated object production apparatus includes a shaping unit 104 in which to form a powder layer and a solidified layer and a material supply unit 105 from which to supply a powdery material to the shaping unit 104. The shaping unit 104 includes a shaping table 140, an elevator 142 for moving the shaping table 140 upwards and downwards and a shaping frame 141 arranged to surround the shaping table 140. The material supply unit 105 includes a storage tank 151 for storing a powdery material, a lifting mechanism 152 and a lifting table 150 for pushing up the powdery material stored within the storage tank 151, and a material supply blade 120 for transferring an upper layer portion of the powdery material stored within the storage tank 151 onto the shaping table 140 and for leveling the surface of the powdery material transferred to the shaping table 140.
With this apparatus, a solidified layer is formed by sintering a specified portion of a powder layer on the shaping table 140 through the use of a solidified layer forming unit (not shown) that irradiates a light beam. Then, the shaping table 140 is moved downwards to form a next powder layer. Formation of the powder layer is performed by moving the lifting table 150 upwards by a short distance, bringing the upper layer of the powdery material stored in the storage tank 151 into a position a little higher than the upper surface of the shaping frame 141, and transferring the powdery material on the lifting table 150 to the shaping table 140 by the sliding movement of the material supply blade 120.
In the apparatus referred to above, it is sometimes the case that the height h2 of the material supply unit 105 becomes twice or more greater than the height h1 of the storage tank h1 in order to allow the lifting table 150 to make up-and-down movement. Such a structure of the material supply unit 105 results in an increase in the size of the apparatus. In addition, the powdery material stored in the storage tank 151 is placed in an open space and is, therefore, apt to be degraded by oxidization or moisture absorption. For that reason, the sintering and curing performed by the light beam becomes uneven, which may possibly reduce the precision and accuracy of the produced object. Moreover, if the powdery material is used up during a forming process and if it becomes necessary to feed the powdery material into the storage tank 151, there is no choice but to stop the apparatus. This leads to reduction in the work efficiency. Additionally, the powdery material is partly splashed in the feeding process thereof, thus making the apparatus dirty. It is impossible to carry out the material feeding operation in an easy and convenient manner.